結果
問題 | No.1171 Runs in Subsequences |
ユーザー |
|
提出日時 | 2020-08-14 22:08:58 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 496 ms / 2,000 ms |
コード長 | 3,471 bytes |
コンパイル時間 | 2,435 ms |
コンパイル使用メモリ | 194,172 KB |
最終ジャッジ日時 | 2025-01-12 23:57:52 |
ジャッジサーバーID (参考情報) |
judge3 / judge2 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 4 |
other | AC * 18 |
ソースコード
#include <bits/stdc++.h> using namespace std; #define rep(i, n) for(int i = 0; i < n; i++) #define rep2(i, x, n) for(int i = x; i <= n; i++) #define rep3(i, x, n) for(int i = x; i >= n; i--) #define elif else if #define sp(x) fixed << setprecision(x) #define pb push_back #define eb emplace_back #define all(x) x.begin(), x.end() #define sz(x) (int)x.size() using ll = long long; using ld = long double; using pii = pair<int, int>; using pil = pair<int, ll>; using pli = pair<ll, int>; using pll = pair<ll, ll>; const ll MOD = 1e9+7; //const ll MOD = 998244353; const int inf = (1<<30)-1; const ll INF = (1LL<<60)-1; const ld EPS = 1e-10; template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;}; template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;}; template<ll mod> struct Mod_Int{ ll x; Mod_Int() {} Mod_Int(ll y) : x (y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} Mod_Int &operator += (const Mod_Int &p){ x = (x + p.x) % mod; return *this; } Mod_Int &operator -= (const Mod_Int &p){ x = (x + mod - p.x) % mod; return *this; } Mod_Int &operator *= (const Mod_Int &p){ x = (x * p.x) % mod; return *this; } Mod_Int &operator /= (const Mod_Int &p){ *this *= p.inverse(); return *this; } Mod_Int &operator ++ () {return *this += Mod_Int(1);} Mod_Int operator ++ (int){ Mod_Int tmp = *this; ++*this; return tmp; } Mod_Int &operator -- () {return *this -= Mod_Int(1);} Mod_Int operator -- (int){ Mod_Int tmp = *this; --*this; return tmp; } Mod_Int operator - () const {return Mod_Int(-x);} Mod_Int operator + (const Mod_Int &p) const {return Mod_Int(*this) += p;} Mod_Int operator - (const Mod_Int &p) const {return Mod_Int(*this) -= p;} Mod_Int operator * (const Mod_Int &p) const {return Mod_Int(*this) *= p;} Mod_Int operator / (const Mod_Int &p) const {return Mod_Int(*this) /= p;} bool operator == (const Mod_Int &p) const {return x == p.x;} bool operator != (const Mod_Int &p) const {return x != p.x;} Mod_Int pow(ll n) const{ Mod_Int now = *this, ret = 1; while(n > 0){ if(n & 1) ret *= now; now *= now, n >>= 1; } return ret; } Mod_Int inverse() const{ return pow(mod-2); } friend ostream &operator << (ostream &os, const Mod_Int &p){ return os << p.x; } friend istream &operator >> (istream &is, Mod_Int &p){ ll a; is >> a; p = Mod_Int<mod>(a); return is; } }; using mint = Mod_Int<MOD>; const int MAX_N = 1e6; mint fac[MAX_N+1], ifac[MAX_N+1]; void init(){ fac[0] = 1; rep2(i, 1, MAX_N){ fac[i] = fac[i-1]*i; } ifac[MAX_N] = fac[MAX_N].inverse(); rep3(i, MAX_N, 1){ ifac[i-1] = ifac[i]*i; } } mint comb(int n, int k){ return fac[n]*ifac[n-k]*ifac[k]; } mint perm(int n, int k){ return fac[n]*ifac[n-k]; } int main(){ string S; cin >> S; ll N = sz(S); mint ans = 0; mint dp[N+1][27]; fill(dp[0], dp[N+1], 0); dp[0][26] = 1; rep(i, N){ rep(j, 27){ if(S[i]-'a' != j) ans += dp[i][j]*mint(2).pow(N-i-1); dp[i+1][S[i]-'a'] += dp[i][j]; dp[i+1][j] += dp[i][j]; } } cout << ans << endl; }